The nearest living ally of Neorinopis sepulta is, with little doubt, Neorina Lowi, which, like the other members of the genus, is found in the Indo-Malayan region. The same is strictly true of the species of Zophoessa, Debis and Lethe, with which we have been obliged to compare this fossil. Cœlites has also been used in comparison, and most of the species of this group belong to the same region, although one is described by Felder from Celebes on the confines of the Austro-Malayan region. We have also pointed out (as Butler has done, but in incorrect points) its relation to Antirrhæa, a Brazilian genus, but this is too distant to be given much weight. The closest allies of N. sepulta are to be found in the Indo-Malayan region.
The same is true, but not to so striking a degree, of Lethites Reynesii. We have compared this also to Debis, Lethe and Neorina, and especially to the two former; and all three of these genera, which are certainly its nearest allies, are strictly confined to the Indo-Malayan region. It is, however, also related, but in a secondary degree, to Enodia, Cercyonis and Maniola, which are genera appertaining to the north temperate zone of both hemispheres.
Coliates Proserpina finds its nearest living representatives in the genus Delias, which also is strictly confined to the Indo-Malayan region. Thyca and Prioneris are closely related, the latter of which is limited to the same district and the former to the Indo-Malayan and Austro-Malayan regions.
Thaites Ruminiana is represented in recent times by the genus Thais, which is confined to the Mediterranean district, within which Aix lies. An allied genus, Archon, is also restricted to the same region. Sericinus, however, and Eurycus, with which we have been obliged to compare it in many points, are found only in the East, the former in China, the latter in Australia; while on the other hand, Parnassius, a genus it quite as much resembles, is limited to alpine and subarctic regions of the northern hemisphere.
The relations of Pamphilites abdita are very different. I have searched carefully for very closely allied forms among East Indian Urbicolæ; but, while it doubtless is not far removed from some of them, its more intimate relationships are certainly with insects from tropical America and especially with Pansydia and Carystus.
Three out of the five Aix butterflies, therefore, find their nearest living allies in the Indo-Malayan region, one is most closely related to forms now found in tropical America and one is at home in its own resting place.
BUTTERFLIES OF THE AQUITANIAN (Lower Miocene).
Thanatites vetula is the only butterfly yet found from this horizon, and this is closely related to Thanaos, a genus belonging to the north temperate zones of both hemispheres, but vastly more developed in the new world, which has at least four times as many species as the old, some of them extending into the subtropical regions. The genera adjacent to Thanaos are purely American, although tropical or subtropical, and therefore the Aquitanian butterfly looks toward subtropical North America for its relatives of the present day.